The moral and ethical problems created by the enslaving of fellow human beings form the underlying theme of Wolf by the Ears. Many readers will as sociate slavery only with the South of the United States, but Colonial New England was also heavily involved with the slave trade, and the keeping of African slaves and their descendants as farm and domestic workers was common practice. Many famous Americans, among them George Washington and Thomas Jefferson, kept slaves on their estates, and although Jefferson promoted human rights, and freed many of his own slaves, he was curiously reluctant to speak out forcefully against the institution of slavery.

The story of the novel is told by one of Jefferson's slaves, a girl named Harriet Hemings, whose mother Sally is the housekeeper at Monticello, Jefferson's home. Rumors among the household link Sally romantically with Jefferson, and Harriet suspects that she, herself, may actually be his daughter as well as his servant. Torn by her love for her home and a desire for freedom, Harriet becomes a symbol of a struggle which, years later, will tear apart the nation and engulf it in one of the bloodiest wars of history, the Civil War between North and South. In spite of being favored and well treated by the master of the house, Harriet longs to be acknowledged as his daughter. The social and political circumstances which keep her from taking her rightful place are the same that eventually precipitate a major national conflict.

Rinaldi brings the problem of slavery close to the modern reader by showing it through the eyes of an intelligent teen-ager.